Toremifene
FARESTON
Pronunciation: tor-EM-i-feen
What it isA triphenylethylene selective estrogen receptor modulator, chemically adjacent to tamoxifen, for metastatic breast cancer in postmenopausal women.
Why this oneTamoxifen-class efficacy with a distinct label; a niche alternative when tamoxifen is problematic.
What limits itQT prolongation distinguishes its label from tamoxifen’s; shares class thromboembolic and endometrial risks.
Toremifene prescription history
Animated chart of estimated U.S. prescriptions per year, Oral anticancer meds (1953–2026). Toremifene enters in 1997 (estimated).
Classes and tags
Clinical profile
Legacy pregnancy categoryD
Defining liabilityQT prolongation and thromboembolic/endometrial risks
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Breast cancer (postmenopausal; indication section not provided — see flags) | Postmenopausal women | 60 mg QD | 60 mg QD until disease progression | 60 mg QD |
Renal PK of toremifene and N-demethyltoremifene similar in renal impairment; no specific adjustment stated
Hepatic Elimination half-life increased <2-fold in hepatic impairment (cirrhosis/fibrosis); exercise caution; no specific adjustment stated
Instructions
- Correct hypokalemia/hypomagnesemia before initiating; monitor electrolytes periodically
- Baseline ECG and as clinically indicated in patients at increased risk
- Periodic CBC, calcium levels, and LFTs; baseline and annual gynecologic examinations
Available strengths
- tab 60 mg
Contraindications
- Congenital or acquired QT prolongation (long QT syndrome)
- Uncorrected hypokalemia or uncorrected hypomagnesemia
Cautions
- QT prolongation/torsade de pointes — avoid QT-prolonging drugs and strong CYP3A4 inhibitors; caution in CHF, hepatic impairment, electrolyte abnormalities
- Hepatotoxicity — Grade 3/4 transaminitis, hyperbilirubinemia, jaundice, hepatitis, NAFLD reported; periodic LFTs
- Hypercalcemia and tumor flare in bone metastases during first weeks — discontinue if hypercalcemia severe
- Uterine malignancy risk — endometrial cancer, hyperplasia, polyps reported; monitor high-risk patients
- History of thromboembolic disease — generally do not treat
- Rare leukopenia/thrombocytopenia — monitor counts in affected patients
Adverse reactions
- Most common: hot flashes (35%), sweating (20%), nausea (14%), vaginal discharge (13%), dizziness, edema, vomiting, vaginal bleeding
- Serious (≥1%): thromboembolic events (pulmonary embolism, thrombophlebitis), MI, ischemic attack
Pregnancy Category D — can cause fetal harm (embryo-fetal toxicity below human dose in animals); premenopausal women must use effective non-hormonal contraception
Lactation Unknown if present in human milk (excreted in rat milk) — discontinue nursing or the drug
Cost
| Strength | #/mo | generic $/mo | CostPlus | |
|---|---|---|---|---|
| 60 mg | tab | 30 qd | $587.97 | offered |
Open Toremifene in the interactive console ↗
Self-check
- Which population has the supplied toremifene indication?
Postmenopausal women with metastatic breast cancer. - What cardiac effect distinguishes toremifene from tamoxifen?
QT prolongation.